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Search Results: 1 - 10 of 1768 matches for " JA Omotoyinbo "
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Effects of Cooling Media on the Mechanical Properties and Microstructure of Sand and Die Casting Aluminium Alloys
BO Adewuyi, JA Omotoyinbo
Journal of Science and Technology (Ghana) , 2008,
Abstract: Die and sand castings are versatile processes capable of being used in mass production of alloys having properties unobtainable by other manufacturing method. In this research, efforts were made to study the effects of cooling media on Aluminium alloy cast. Aluminium scrap (Al – Mg – Si,) were charged into crucible furnace from which as-cast aluminium samples for the experimental work were obtained. The specimens were subjected to hardness test, tensile test and metallographic examination. The results show that samples obtained from air cooled dies had the best mechanical properties and those produce by sand casting had comparable hardness values but lower tensile properties. Other results show that the hardness of cast alloys can be varied by changing the cooling media.
Determination of the Level of Contamination of Underground Water (hand- dug well) by Organic Waste: A case Study of Ado-Ekiti, Nigeria.
OS Omotoyinbo
Ethiopian Journal of Education and Sciences , 2007,
Abstract: The recent increase in urbanization has lead to increase in city population, spatial size, and generation of waste. This is a common phenomenon in Nigeria Cities, where Ado-Ekiti is a typical example. With the ever increasing population coupled with increasing waste (contaminant) generation and high demand for potable water, there have been reported cases of water associated health problems in the state specialist hospital. The aim of this study is to determine the level of contamination of hand-dug well which is one of the major source of water supply for the population. Water samples were taken from a total of fifteen wells at the vicinity of three major refuse dumpsite taking measurement of depth of the well, diameter, volume of water, distance to toilet and dumpsite and the physical condition of the wells. The determination of bacteria level was done using, Experimental scientific set standard. The total coliform bacteria count shows that the water is exposed to serious and complex contaminations, which indicates source pollutant of sewage and faecal materials from man and animal. With the findings, location, design and construction of wells should not be determined by only hydro geological facts, but a set standard that will put distance from toilet/dumpsite into consideration should be strictly followed. Also health workers should carry out regular monitoring of the well for contaminations. Ethiopian Journal of Education and Sciences Vol. 3 (1) 2007: pp. 43-50
Working Properties of Some Selected Refractory Clay Deposits in South Western Nigeria  [PDF]
J.A. Omotoyinbo, O.O. Oluwole
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2008, DOI: 10.4236/jmmce.2008.73018
Abstract: Working properties of some clay deposits in Ekiti State, Nigeria were investigated with a view to determine their suitability for use as refractory bricks. The samples were collected from three different commercial pottery clay centers in Ekiti State; they are Ara, Awo and Isan. Two varieties were collected from both Ara and Isan, which are named Ara 1, Ara 2, and Isan 1, Isan 2 respectively while only one type was collected from Awo. The clay samples were crushed, pulverized, sieved and their chemical compositions were determined. The clay samples were treated separately as well as blended together in different proportions and moulded into bricks. The bricks were dried and fired to 1050℃. Tests for refractoriness, thermal shock resistance, shrinkage, thermal expansion; bulk density, porosity, and compressive strength were carried out on each batch specimen. The results showed that Ara 2 and Ara 1, 2 combined in equal proportions displayed the highest thermo chemical stability. They also possess comparatively high cold crushing strength, and high thermal shock resistance, but definitely not the highest. The apparent porosity of all the batch specimens was found to be high as well as the bulk densities, while the shrinkage of all the specimens were low. It was concluded that 100% Ara 2, and a blend of Ara 1 and 2 in equal proportions, are most suitable for production of crucibles, and furnace lining for non ferrous metals processing, such as Aluminium, Lead and Bronze.
The Effect of Plastic Deformation and Magnesium Content on the Mechanical Properties of 6063 Aluminium Alloys  [PDF]
J.A. Omotoyinbo, I.O. Oladele
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.96038
Abstract: In order to determine the effect of increased magnesium addition on the strengthening behaviour during deformation, four types of aluminium alloys were cast and rolled. The cast aluminium alloys contain; 0.451%Mg, 0.551%Mg, 0.651%Mg, and 0.751%Mg in addition to the other elements which are constant. Deformation was carried out at 20% and 40%. The hot worked profiles were machined into tensile test specimen and were subjected to tensile test. The result was used to determine the ultimate tensile strength and the percentage elongation. From the results, it was observed that the tensile properties of the aluminium alloys improved with increase in percentage deformation and magnesium content up to 0.651%Mg. This shows the effect of deformation on grain refinement. At high percentage of deformation and increased magnesium content, the grains are more refined and this improves the strength and the mechanical properties. However, at 0.751%Mg, a decrease in the tensile properties was observed as deformation is no more effective. The result shows that there is a limit to the amount of magnesium content that will give the optimum mechanical properties.
Evaluating the Influence of Ageing Temperature on the Mechanical Properties of Al-Mg-Si Alloy  [PDF]
I.O. Oladele, J.A. Omotoyinbo
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.1014101
Abstract: The effect of ageing temperature on the mechanical properties of Al-Mg-Si alloy has been studied. The material was machined into different shapes of the tests to be carried out: tensile, impact and hardness. The test specimens were divided into two and, some sets were solution treated at 500℃ for one hour and peak aged at 160℃ for eight hours while the other sets were solution treated at 500℃ for one hour and peak aged at 180℃ for eight hours. The abovementioned tests were carried out on the specimens. The results show that at low ageing temperature of 160℃, the ductility and impact were high while at 180℃, the ultimate tensile strength and hardness are higher compared to the value obtained at 160℃.
Mechanical Properties and Microstructures of Locally Produced Aluminium-Bronze Alloy  [PDF]
Uyime Donatus, Joseph Ajibade Omotoyinbo, Itopa Monday Momoh
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.1110105
Abstract: This work studied the feasibility of producing a dual-phase aluminium bronze alloy and the use of selected treatments to manipulate the mechanical properties of the produced alloy using local techniques, as a potential replacement for con- ventional structural materials, particularly steels. Sand casting was used and was found to be effective based on its ad- vantages of low cost, ease of use and flexibility in the production of a dual-phase aluminium bronze alloy with pre-selected composition of 11% Al content. Cold deformation of 10 and 20% degrees and selected heat treatments were used on the cast alloy to influence its mechanical properties. The selected heat treatments are solution heat treat- ment, normalising, and ageing. The results showed that normalising gave the optimum mix of tested mechanical proper- ties with ultimate tensile strength in the range of 325 MPa, elongation of around 60% and Rockwell hardness values of 46.5 - 63.7 HRc, making this alloy suitable as alternatives to steel in low/medium strength structural applications.
Effect of Crude Oil-Contaminated Soil on Germination and Growth Performance of Abelmoschus esculentus L. Moench—A Widely Cultivated Vegetable Crop in Nigeria  [PDF]
A. A. Oyedeji, A. O. Adebiyi, M. A. Omotoyinbo, C. O. Ogunkunle
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.310174
Abstract: This study investigated the effect of crude oil-contaminated soil on the germination and growth performance of Abelmoschus esculentus, a widely cultivated vegetable crop in Nigeria. The experiment was conducted in the Screen House, under controlled environmental conditions. The seedling emergence percentage, heights and girths were studied to determine the growth performance of the crop in crude oil-contaminated soil. The result of the investigation revealed that the crude oil-contaminated soil affects the growth performance of Abelmoschus esculentus L. as hindered germination, reduced heights and girths were observed in the crop planted in treated soil and this adversely and severely affects the crop agronomic growth and development and probably its yield. Therefore, contamination of agricultural soils with crude oil should be avoided and public awareness should be created on the detrimental effects of crude oil pollution in our terrestrial ecosystem. Innovative and environmental-friendly remediation strategies should be carried out on our agricultural soils that have been grossly polluted by crude oil exploitation and exploration.
Effect of welding current and voltage on the mechanical properties of wrought (6063) aluminium alloy
Oluwole, Oladele Isiaka;Ajibade, Omotoyinbo Joseph;
Materials Research , 2010, DOI: 10.1590/S1516-14392010000200002
Abstract: this work was carried out to investigate the effect of welded joints on the mechanical properties of wrought (6063) aluminium alloy. the study revealed the influence of current and voltage on the welded joint as well as the mechanical properties of the alloy. the alloy samples were welded together by metal inert gas welding process at varying values of current and voltage after which mechanical tests were performed on the welded samples. the microstructural examination of the various fusion zones obtained was carried out. appreciable variations in the properties of the welded samples were observed due to changes in the microstructural features of the alloys. it was concluded that variation of current and voltage remarkably affect the mechanical properties of the wrought 6063 aluminium alloy. as the voltage increases from 25 to 30 v, the ultimate tensile strengths and hardness values increases while the impact strengths decreases but the current did not show such trend.
Influence of Rock Mineralogy on Subsurface Water in Ado-Ekiti, Nigeria
O S Omotoyinbo, F C Okafor
African Research Review , 2008,
Abstract: Sudden geometric increase in population of Ado-Ekiti has lead to an increase in demand for water and harnessing of subsurface water reserve. This research investigated the possible infiltration of dissolved mineral from weathered rock into subsurface water in the area (basement complex rocks), and comparing the mineral level with the set standard for quality water by the World Health Organization Physical test were carried out on hardness, colour, odour, conductivity, pH, and turbidity. Chemical test for sodium (Na+) and potassium (K2+) was also done using experimental scientific set standard. The analysis of the sodium, potassium ions, and the conductivity of the water indicate that dissolved mineral from rocks have great influence on the underground water property. The level of the dissolved mineral is within the acceptable limit for water quality standard set by the W.H.O. Sourcing for underground water should not be based on hydro geological variable alone but possible chemical interference from the geology of the environment (rock type). African Research Review Vol. 2 (2) 2008 pp. 175-186
Investigating the Effect of Chemical Treatment on the Constituents and Tensile Properties of Sisal Fibre  [PDF]
I.O. Oladele, J.A. Omotoyinbo, J.O.T. Adewara
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.96041
Abstract: This work was carried out to investigate the effect of chemical treatment on the constituents and tensile properties of sisal fibre (Agave Sisalana). Sisal leaves were cut and buried underground close to the stream and were wetted with water regularly in order to ensure proper fermentation for about 15 days. The fermented leaves were washed and sun dried. The dried sisal fibre obtained was treated mechanically with chemicals after which the percentages of their constituents were characterized and, their tensile properties determined with Instron universal tensile testing machine. The results show that the chemical treatments enhance the removal of lignin and hemicelluloses which are detrimental to the bonding strength of composite produced from natural fibres except that of sample treated with alkaline peroxide. The results of the tensile test revealed that sample treated sequentially with KOH, acetic acid, NaCl and HCl has the best tensile properties followed by the sample treated with alkaline peroxide.
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